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Members of this genus are generally dark brown (Thomasson and Post, 1966) and the head is slightly longer than broad and has transversely anastamosing striae. The cheeks are somewhat serrate and have pairs of small setae. The eyes bulge slightly and ocelli may be present or absent. The postocular setae are well developed and the antennae are 8 segmented. Antennal segment 3 is small and lacks sense cones, while segment 4 has a minimum of 1 inner and 1 outer sense cone, and segment 8 is long and slender. The maxillary stylets are slender and retract far into the head. The mouth cone is long and varies in shape from pointed to blunt. The thorax may be smooth or weakly sculptured, and the epimeral sutures may or may not be complete. The basantra is absent and the mesospinasternum is lacking. Species in this genus are mainly brachypterous, though occasionally macropterous. When specimens are macropterous, they lack accessory cilia on the forewings. The pelta is broad with transverse anastomosing striae. The wing holding setae are absent in brachypterous forms and weakly developed in macropterous forms. Major posterior setae on tergite 9 are short, and the tube is nearly the length of the head (Stannard, 1968).